Liquid and gas transfer in mercury switches



2 Sheets-Sheet 1 P 1948- E. w. RICKMEYER 2,448,687

LIQUID AND GAS TRANSFER IN MERCURY SWITCHES Filed 001:. 26, 1945 2Sheets-Sheet 2 Patented Sept. 7, 1948 UNITED? STATES: PATENT OFTTI'CIE-tv LIQUIDQAND. GAS TRANSFERIN MERCURY SWITCHES".-

Ernst :Walter Rickmeyer, Berkeley, 1111;,":aassig'nor toe-JeffersonElectric Company; Bellwood; I112, a corporation of Illinois 8 Claims, 1

The 'present invention relates to" a mercury switch, and moreparticularly to-a switch in which a cup like element having-relativelyporous walls divides-the switch envelope into two chambers.

Mercury is normally ilcontainednin one.of these chambers and," underecertain r conditions, is adapted to pass through the porous, wallsofthe cup into the other chamber; In a mercuryswitch anenvelope isusually provided with'a pair of electrical conductors fastened theretoin such a the switch envelope; One of .theconductors is usually fastenedto an electrode that=projects into the; envelope and into the-pooloft-mercury therein; The mercury, in turn, is electrically connected tothe other conductorsoas to complete the circuit inZtheQenVeIopeLwHInorder -to -breakrthe vcircuit thacontact-between the mercury and'the'electrode is-broken Thiscanxbe accomplished by moving the-electrode outof'theupool of mercury oreby -mo ving1the-pool of --mercury away from:the electrodev-so-that the two are no. longer incontact;v The-presentinvention wpertains to a switch of-.'the latter type wherein the-body ofmercury is moved relative tea-stationary electrodesmas tocbreak theelectrical contaot.therebetween.

As previously mentioned, a cup-like elementis used ,to -divide theswitch element intotwo cham bers.. L The electrode and the. mercury are.nor-. mally disposed in one of these chambers with the electrode atleast partially immersed rin the mercury. In order to break the circuit.the mercury is camed to flow. or pass through the walls'uof the cup likeelementlinto the second chamber to thereby lower the level of themercurypool in the'first chambersufliciently to physically separate the mercuryand the electrode. This passageof mercury through the Walls'of thecuplike element is accomplished under certain'jcircumstanceswherethemercury is causedto apply of'flow of the mercury through thewalls.

A mercury switch of this typethatis intended to operate at differentspeedsofrotation to pro-- vide different time-delay features in breakingthe circuit between the mercury andelectrode, in -thepast have i notbeen satisfactory at high speedsf vl manner. as. .to= lie-electricallyconnected through. I the medium of a pooli'ofumercury contained .in

Thereasonforthis is that the greater centrifugal" force caused by:highf-ro tati-ng speeds forces the; mercury through'the walls of thecup-like element too*-fast so' as: to canse the circuit to bebrokerrbefore-it is desired todoso.

The present invention is intended to overcome' this difiicultyand toprovide a switch of this type"- that' has dependable time delaycharacteristics i both atlow and highspeedsof rotation.

The foregoing constitute some of the principal objects and advantages ofthe-present. invention" others of which 'will become apparent from the 1following description-and drawings; in which FigE-l is a longitudinalsectionalview through a mercury switch and showing the cup-like elementembodying the-present invention;

Fig"; 2 is an end elevation view of the mercury" switch 'showrr in Fi'g;-1, the view'being-take'n at the left handside of the device shown inFig'; 1;

Fig.8 is a transverse sectional view through the mercury switch-"theview being taken on the" line Fig= 4 is a transverse sectional viewthrough the bottom support for the cup-like element, the view beingtaken on theline of 4-4 of Fig.- 1;

Fig? 5 is a sectional view corresponding to Fig. 1 butshowing 'a secondembodiment of the present invention and i Fig-=6 is -a diagrammaticalview ofa mercury switch shown mounted on a revolvable disk.-'

Two specific embodiments of the present invention have been: selectedand will be described herein in compliance with Section 4888 of-therevised -'sta'tutes. It is recognized that many scope of thexinvention.1

Referring now-to Fig." '1 the invention is shown in conjunction with *amercury switch generally indicatedatalS 'which'comprises a switch en--velopevlfi, closed at the bottomas at H and open at-the top'to receiveanelectrode lit-that projects through the opentop'into the envelopeinterior." Theelectrode IB-is provided with a shoulder l9 against whichrests -an'insulat'ingwasher 20. A second Washer2| is inserted betweenwasher 20 and the rim -portion 22*of the envelope l5'that Additional tsurrounds the open-- end thereof.

wash'ers23fi24, 'and '25 surround the electrode l8 and cooperate withthe rim portion 22 0f the envelope l 5 to support the electrode 18. IEach of" these-washers 20, 2 l-,= 23, 24;and-25 comprises some suitableinsulating-material such, 'for ex amplef aspolystyrene.'- Th'e upperendof the modifications will occur-to one-skilled in the art, audit isintended that 'such modificationsmay be made-+ withoutmdeparting fromthe intended electrode i3 is turned over as at 2% to provide a shoulder,and a washer 21 of good electrical conducting material is insertedbetween this last mentioned shoulder and the upper insulating washer 25.To this washer 21 is secured one of the electrical conductors 28, andthe other electrical conductor 23 is secured to a ring member thatsurrounds the envelope [6 and is held in electrical conductingrelationship therewith.

The envelope I6 is provided with a shoulder portion 3| adjacent to theupper end thereof and a cup-like member 32 is disposed inside theenvelope I6 between this ofiset portion 3| and the bottom ll of theenvelope [6. The bottom I! of the envelope i6 is held in place by meansof a turned over portion 33 of the side walls of the envelope I3 and awasher 34 is inserted between this over-turned portion 33 and the bottomI! of the envelope. The cup-like member 32 is provided with outwardlyprojecting supporting members 35 (Figs. 1 and 4) that rest against thebottom portion of the envelope. In the preferred embodiment of theinvention shown in Fig. 1, this cup-like element 32 has tapered sidewalls that are provided with alternate diagonally offset or steppedportions 36 and vertical portions 31 which merge into a bottom portion38 of narrower diameter than the upper portion of the cup-like member32. The side walls of this cuplike member 32 together with the bottomwall 38 comprise a porous metallic material so that mercury undercertain circumstances may be forced through these walls. A sinteredpowdered nickel is a suitable material for the cup-like member.

In the normal operation of the mercury switch shown in Fig. 1, mercuryis contained inside the cup-like member 32 in such a manner as tocomplete an electrical connection from the outer walls of the envelopeHi to the electrode l8. This mercury switch 15 may be mounted on arotatable disk shown in Fig. 6 at 40. This disk 43 may be mounted on ashaft 4! so as to be rotatable thereabout. The mercury switch is shownat IS in Fig. 6 disposed with its bottom wall I! farthest removed fromthe center of the disk 40. As the disk 40 is rotating about the shaft4|, mercury that is disposed within the cup-like element 42 (Fig. 1) isforced by centrifugal force outwardly against the bottom 38 of thecup-like portion 32. As this centrifugal force reaches a predeterminedamount corresponding to some preselected speed of rotation of the disk40, the mercury is caused to flow through the bottom wall 38 of thecup-like member 32 into a separate chamber indicated at 42 in Fig. 1.The air in this chamber 42 thus displaced by the mercury is forced alongthe tapered sides of the cup-like member 32 and passes through theporous walls so as to equalize the pressures on both sides of the wallsof the cup-like member.

During this rotation of the mercury switch l5 the step-like portions 36of the walls of the cup 32 create turbulence in the flow of mercury soas to reduce the amount of mercury that would otherwise be disposedagainst the bottom wall 38 of the cup-like member 32. In this manner athigh rotating velocities of the mercury switch l5 only a fraction of themercury will be disposed against the lower face 38 of the cup-likemember 32, the remainder of the mercury being held back against the sidewalls of the cup-like member by the turbulence. Thus the effects at highrotating speeds is minimized to the extent of the turbulence so as toreduce the rate of flow through the bottom wall 38 of the cup-likememher 32. At lower rotating speeds of the mercury switch 15, there isless turbulence in the flow of the mercury so that under theseconditions a greater proportion of the mercury is disposed against thebottom wall 38 of the cup-like member 32. Thus at these lower rotatingspeeds a greater force is applied by the mercury against the bottom wall38. Thus by means of creating turbulence in the mercury, compensatingmeans are provided for differences in centrifugal force caused atdifferent rotating speeds of the mercury switch.

In Fig. 5 a second embodiment of the invention is shown. In thisarrangement the cup-like element is shown at 45 and has relativelystraight sides 45 flared only at the top as at 41 and slightly taperedat the bottom at 48. Projecting inadequately from the walls of thecup-like member 45 are angular, incline baffle members 43. As shown,there are two of such members 43, the lower one of which is indicated at49a and projects further into the cup-like member than the upper bafilemember. These inadequately projecting members 49 and 49a produce theturbulence in the flow of the mercury in the manner previously describedwith respect to the first embodiment of the invention.

As shown in Fig. 4 the projections 35 at the bottom of the cup-likemember 32 comprises a plurality of segments 35a spaced apart to providepassages therebetween through which the mercury may escape in the eventthat it is trapped between these segments 350..

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a mercury switch of the class described a switch envelope, arelatively porous cup in the envelope adapted to contain a body ofmercury and dividing the envelope into two chambers, the mercury beingadapted to flow from within the cup to the second chamber through theporous walls of the cup, said cup comprising tapered walls, and slopingmeans on the walls for causing turbulence in the flow of mercury fromone chamber to the other.

2. In a mercury switch of the class described a switch envelope, aporous dividing wall in the envelope forming two separate chambers, thewall being cup shape with tapered walls, and sloping surfaces on theinner faces of the walls projecting into the cup.

3. In a mercury switch of the class described an elongated switchenvelope, a porous cup in the envelope extending lengthwise thereof andhaving tapered walls, the cup dividing the envelope into two chambers,and inwardly projecting surfaces on the walls of the cup, saidprojections sloping toward the bottom of the cup.

4. In a mercury switch of the class described, a switch envelope, aporous cup in the envelope with its bottom disposed adjacent to one wallof the envelope, the sides of the cup at least for a portion of thelength of the cup being spaced from the envelope walls so that the cupdivides the envelope into two chambers, and inwardly projecting surfaceson the walls of the cup, the surfaces sloping toward the bottom of thecup.

5. In a mercury switch of the class described, a switch envelope in theform of a cylindrical shell, an inner porous cup having one end adaptedto engage the inner face of the shell, the walls of the cup beingtapered toward the other end of the cup, the walls of the cup beingprovided with inwardly projecting surfaces sloping toward the cupbottom.

6. In a mercury switch of the class described, a switch envelope, aporous cup in the envelope with its bottom disposed adjacent to one endof the wall, the sides of the cup at least for a portion of the cuplength being spaced from the envelope walls so that the cup divides theenvelope into two chambers, the side walls of the cup comprising aplurality of cylindrical segments of progressively narrower diameterfrom one end of the cup to the other end of the cup, and tapered wallsegments connecting adjacent segments.

7. In a mercur switch of the class described,

a switch envelope, a porous cup in the envelope with its bottom disposedadjacent to one end of the wall, the sides of the cup at least for aportion of the cup length being tapered toward the bottom of the cup,and a plurality of inwardly projecting porous baflle members supportedby said walls, these baflie members sloping toward the bottom of thecup.

8. In a mercury switch of the class described, a switch envelope, adividing wall in the envelope in the form of a sintered metal cup havingtapered walls, and sloping surfaces on the inner faces of the wallsprojecting into the cup.

ERNST WALTER RICKMEYER.

